Roundabouts

Roundabouts have become common fixtures on Michigan’s roads. The State’s first roundabout was built in 1996 by the Road Commission for Oakland County. Roundabouts quickly gained popularity due to their ability to enhance safety and reduce congestion. According to the Insurance Institute for Highway Safety, a modern roundabout provides a 39% reduction in total crashes and a 90% reduction in serious injury and fatality crashes.

While today’s drivers’ education courses do include lessons on driving roundabouts, many of us received our licenses before we encountered our first roundabout. It is important that motorists, bicyclists, pedestrians, and commercial vehicle operators understand the golden rules of traveling roundabouts:

Yield and wait for a safe gap in circulating traffic before entering the roundabout. Do not merge into the roundabout like you would with a high-speed freeway entry ramp.

Avoid changing lanes within a multi-lane roundabout.

Do not stop inside the roundabout unless traffic conditions require you to do so.

Frequently Asked Questions

Vehicles that are inside and circulating through the roundabout always have the right of way. Motorists or bicyclists who want to enter the roundabout must yield to all lanes and wait for a safe gap in circulating traffic to enter the roundabout. In some instances, this means motorists must stop at the yield sign until a gap is present.

When approaching a multi-lane roundabout, look for the posted signs that indicate the correct lane to enter the roundabout. Selecting a lane in a roundabout is similar to selecting a lane at a traffic signal– right-hand turns generally stay in the right-most lane while left-hand turns generally select the left lane. Signage will tell you which lane to choose if you want to continue straight through the roundabout. Remember to use a turn signal to indicate as you approach your exit to let others know they can enter the roundabout.

Avoid changing lanes while in the roundabout and only stop inside the roundabout to avoid a collision. Crash incidents are greatly reduced when drivers choose the correct lane and yield to all lanes when entering a roundabout.

Many of WCRC’s roundabouts have been funded with federal safety or congestion/air quality (CMAQ) grants. These grants are not eligible for use to repair and surface roadways. WCRC staff applies for CMAQ grants with a specific intersection in mind, typically one with a higher incidence of crashes or congestion issues. The federal government make the final determination in approving a project’s funding. Because federal aid grants are project-specific, WCRC is not taking funding away from other projects. To learn more about how road funding works, visit our Road Funding page.

According to the Institute for Highway Safety, a modern roundabout provides a 39% reduction in total crashes and a 90% reduction in serious injury and fatality crashes. There are two design features of roundabouts that make it a safer intersection option. The circular shape of the central island which reduces vehicular speeds and prevents the high-speed, T-bone collisions seen at traditional intersections. The splitter islands at each approach also reduce traffic speeds upon entry, serve as a refuge for pedestrians, and instruct motorists to YIELD to all lanes and wait for a safe gap to enter the roundabout.

After a roundabout is built, there can be an initial spike in low-impact, non-injury crashes (fender benders), but it’s important to keep in mind that roundabouts practically eliminate life-threatening injuries that occur at signalized and stop-controlled intersections. While these nuisance crashes are not ideal, the number of fender-benders typically decreases as motorists become more familiar with the roundabout.

Sometimes truck drivers use the concrete apron which is present along the outer edge of the roundabout’s central island. Other times they straddle two lanes of traffic to circulate through multi-lane roundabouts. It is important to respect large trucks by giving them space to maneuver inside a roundabout. Being aggressive and “jockeying for position” to beat a large truck in a roundabout can result in a sideswipe collision. Some states like Wisconsin and Oregon give total right of way to the truck inside of a roundabout, thus making it illegal to pass them.